The trend in the circuit protection industry is currently toward complete circuit protection which is accomplished by the addition of supplemental protection apparatus to standard overcurrent protective devices, such as molded case circuit breakers In the past, when such auxiliary protection apparatus or other circuit breaker accessories were combined with a standard circuit breaker, the accessories were usually custom-installed at the point of manufacture. The combined protective device, when later installed in the field, could not be externally accessed for inspection, replacement or repair without destroying the integrity of the circuit breaker interior. An example of one such factory installed circuit breaker accessory is found in U.S. Pat. No. 4,297,663 entitled "Circuit Breaker Accessories Packaged in a Standardized Molded Case", which Patent is incorporated herein for reference purposes.
A more recent example of a circuit breaker including additional accessories is found in U.S. Pat. No. 4,622,444 entitled "Circuit Breaker Housing and Attachment Box" which allows the accessories to be field-installed within the circuit breaker without interfering with the integrity of the circuit breaker internal components. This is accomplished by mounting the accessories within a recess formed in the circuit breaker enclosure cover.
An electronic trip actuator which is mounted within the circuit breaker enclosure is described within U.S. Pat. No. 4,679,019 entitled "Trip Actuator for Molded Case Circuit Breakers". The circuit breaker actuator responds to trip signals generated by an electronic trip unit completely contained within a semi-conductor chip such as that described within U.S. Pat. No. 4,589,052. The development of a combined trip actuator for both overcurrent protection as well as accessory function is found within U.S. Patent 4,700,161 entitled "Combined Trip Unit and Accessory Module for Electronic Trip Circuit Breakers". The aforementioned U.S. Patents which represent the advanced state of the art of circuit protection devices are incorporated herein for reference purposes.
An integrated protection unit having both overcurrent protection along with a shunt trip accessory unit is described within concurrently filed U.S. patent application Ser. No. 133,867entitled "Molded Case Circuit Breaker Shunt Trip Unit" and U.S. patent application Ser. No. 133,869 entitled "Molded Case Circuit Breaker Multiple Accessory Unit" which Applications are incorporated herein for purposes of reference.
When the integrated protection unit is located remotely from the protected industrial equipment, it is important for the equipment operator to ascertain the status of the operating power supplied to the equipment. An auxiliary switch, installed within the breaker enclosure at the factory interacts with the circuit breaker operating mechanism to provide an electronic indication of the "ON - OFF" condition of the circuit breaker contacts, usually by means of color-coded indicating lights.
One purpose of the instant invention is to provide an auxiliary switch unit which is field-installable and which is capable of indicating the conditions of the circuit breaker contacts at a location remote from the circuit breaker.